new york city mayor michael bloomberg has been leading the way. >> words alone cannot heal our nation. only action can do that. gun violence is a national epidemic and a national tragedy that demands more than words. >> this hour senator dianne feinstein about her push to reinstate the assault weapons ban. >> it's a first day bill i'm going to introduce in the senate and the same bill will be introduced in the house. a bill to ban assault weapons. it will ban the sale, the transfer, the importation and the possession. not retroactively, but perspectively, and it will ban the same for big clips, drums, or strips of more than ten bullets. >> as the nation mourns 20 children and six women who tried to save them, some of the teachers who survived talk to matt lauer. >> it just kept going, so the noises that i started to hear were pops and, of course, i then at that point said, you know, we've got to do this lockdown. >> immediately the leaders in our building did what they needed to do, and they ran out of the door knowing that that gunfire was showering the hallways and the classrooms. >